Grinding the teeth of mowers and reapers



UNITE sTATEs PATENT orrrcn.

DAVID HINMAN, OF BELEA, OHIO.

GRINDING THE TEETI-I OF MOWERS AND REAPERS.

Specification of Letters Patent No. 25,412, dated September 13, 1859.

T o all whom it may concern:

Be it known that I, DAVID HINMAN, of Berea, in the county of Cuyahoga and State of Ohio, have invented new and useful Improvements in Grindstones for Mower and Reaper Cutters; and I do hereby declare that the following is a full and complete description of the construction and operation of the same, reference being had to the accompan ing drawings, making part of this speci cation, in which- Figure l is a perspective view. Fig. 2 is a top view, and Fig. 3, is a section of the stone.

Like letters refer to like parts.

The nature of my invention consists in such a form of the stone, and other devices connected therewith, that mower and reaper cutters may be ground at a uniform bevel and closely into the angle between the blades, and at the same time to preserve the form of the stone unimpaired.

A A in Figs. l and 2 represent the frame upon which the stone is hung. This may be formed of two planks of about one foot width each, and three feet long, put to gether in the form of the letter T. The three extremities of the frame thus formed are provided with legs of convenient length, as seen at A A.

B, represents the shaft of the grindstone. This shaft is placed in boxes O C and lies along above the center of the body of the frame A, and crosses the center' of the piece A. The stone D, is securely attached to the outerend of the shaft being that which rests upon or within the box C. The crank E, is attached to the opposite end of the shaft, as seen in Figs. 1 and 2.

Upon each end of the piece A, rises an oblique standard, seen at F and Gr, both of which project in front of the face of the stone, as seen at F and Gr. To the top of the standard F, is attached by a pin which is placed .upon a line with the center of the stone, the vibrating bar or holder H. This bar or holder can be vibrated from I to J as indicated by the dotted lines.

For the purpose of forming grinding surfaces, I cut in one or both sides of the stone circular grooves or channels a ce, leaving an annular ring or projection c c, of from two and a half to three inches wide, upon one or both sides, and these form the grinding surfaces. The width of these annular rings or projections should be suoli that the point of the cutter' when applied as hereinafter stated, will reach nearly or quite to the channel or circular groove a. By this means, the whole of the grinding surface of the stone can be kept true and at right angles to the line of the shaft.

In grinding the cutters, the point of the one next to that which is to be ground is placed upon the face of the projection G, in such a position that when the bar is inclined slightly outward the face c, of the stone will accurately fit the bevel of the cutter. The bar or holder H, is then adjusted so as to bring the bar between two cutters as seen at z' in Fig. 1. Now, by revolving the stone in the direction of the arrow, the grinding will be accurately performed. During this operation, the cutter bar must be held firmly and steadily in the proper position. Then all the edges in one direction have been ground, the cutter bar should be placed upon the opposite side of the stone, where the process of grinding can be completed upon the opposite edge. The position of the cutter bar upon either side, is indicated by the dotted lines L M in Fig. 2.

Vhat I claim as my improvement and desire to secure by Letters Patent is,

The circular' grooves cv, a, on the faces e, e, of the grindstone, in connection with the standards F F", G G and holder H, arranged and operating in the manner specified.

DAVID HINMAN.

lVitnesses J. BRAINERD, S. H. MATHER. 

